The automation of photography has always been of interest, but has received increasing attention over the past few decades. Automatic exposure control and auto-focus are now standard features on most cameras, and many cameras have other electronically controlled or electrical features. Video and still cameras with electronic image sensors in the form of one or more photosensitive arrays are becoming increasingly available to the public, and are popular since they provide facilities not previously available, including the means to record images cheaply, to select edit and print only those images which are considered acceptable, and to do so at home using only a PC and ancillary equipment, and to transmit and receive images using e-mail.
However, in general, cameras bought off the shelf still require an operator to decide upon the composition of the actual picture to be taken, including decisions as to picture framing (direction and zoom) and timing. While the advent of electronic cameras does provide the ability to record a number of pictures in sequence, or even a video clip, from which a suitable image can then be selected, and while this can be followed by a degree of editing, the operator still has to point the camera in generally the correct direction and to press the operating button at around the correct time.
Since both still and video electronic cameras have sensors capable of providing a sequence (not necessarily regular or continuous) of image signals they will be broadly referred to herein as “electronic cameras”. The output thereof will be referred to as a “video signal” irrespective of whether it represents a still or moving image, and whether the video signal is recorded at the camera or elsewhere. References to a picture or image should be read as covering both stills and video sequences.
Camera controls such as autofocus and exposure relate more to the technical side of picture taking. These have little or nothing to do with picture composition, including framing and timing, but there is now increasing interest in this latter aspect and the provision of intelligent still and video cameras which have a facility for picture taking or picture selection where conscious operator input is either further reduced or eliminated altogether.
One possible solution is to store the whole of the video signal from a continuously operated camera and manually to select suitable images of image sequences therefrom at a later period. While this reduces the burden on a camera operator, or avoids the need for a camera operator altogether, not only does this approach require a very large amount of video storage, but if a human operator is later required to inspect the stored image during the selection process it is also very time consuming and thus expensive. Therefore it is highly desirable either to have at least some degree of image selection before storage, or, if the whole signal is stored, to record therewith a further signal indicative of where the most interesting portions of the signal are likely to be found.
Known types of automatic camera apparatus in which a degree of picture composition is effected encompass a broad spectrum. At one end lie forms of equipment in which the conditions for picture taking are strictly predetermined and extremely restricted, for example booths for taking passport photographs where the camera is operated with a fixed timing after a seated customer in an essentially fixed position has put money into the machine.
More freedom is permitted in apparatus where picture taking is automatically triggered in response to a predetermined condition or set of conditions, for example in response to the outcome of an algorithmic computation operating upon the output of one or more sensors. However, one problem with apparatus of this type is in defining the set of conditions necessary for picture taking to be enabled.
In certain circumstances, the prescribed conditions are physically predetermined. Security cameras which commence operation in response to an alarm input, and traffic speed cameras which respond to a vehicle being driven too fast, fall within this category. It is also known to take pictures of visitors on a ride at a theme park by triggering a suitable located fixed camera which is actuated when the car in which the visitor is riding trips a switch, such as by cutting an infra-red beam. Such systems are disclosed in International Patent Application No. WO 98/10358 (Goldberg), European Patent Application No. 0 953 935 (Eastman Kodak), U.S. Pat. No. 5,655,053 (Renie) and U.S. Pat. No. 5,576,838 (Renie) for example.
Other systems allow rather more latitude, by recognition or detection of a feature associated with the feature to be imaged. Thus U.S. Pat. No. 5,844,599 (Hildin) discloses a video camera system for use with a group of people around a conference table, where each person wears a microphone, and the camera is arranged to respond by being directed towards the person who is speaking at the time, and to track the movements of that person. This is a system more intended for viewing than image recordal. European Patent Application No. 0 660 131 (Osen) describes a system where global positioning systems are employed to track a feature, such as an aircraft, so that cameras can be automatically directed thereto.
In this respect, use is increasingly being made of tags for identifying features being imaged/or for triggering the camera. This occurs in U.S. Pat. No. 5,694,514 (Evans) and in International Patent Application No. WO 98/10358 (Goldberg) mentioned above to enable pictures of different features to be easily identified. The latter application describes a number of camera systems including the use of a tag to actuate a camera and to provide data for associating the image with the person wearing the tag; in a variant, facial recognition is used to identify the feature, working from an image and other relevant data initially fed into the system.
However, compared with a personal camera user who can employ a hand-held camera at any time and wherever they are to take pictures of anything considered to be of interest, in all of the prior art mentioned above there remain significant restrictions as to the manner of picture taking. Most known automatic camera apparatus either employs a fixed camera and/or has narrow limitations on the circumstances under which the camera is triggered, e.g. in response to a tag or a conditional or alarm input associated with a restricted condition or set of conditions. In commercial installations such as theme parks, the cameras are essentially fixed and located to capture an image under specific circumstances, for example where it is anticipated that at least some of the stored images will prove to be sufficiently composed and appealing to be of interest to a would-be purchaser.